This invention relates to a power supply configured as a battery pack, electrical (electronic) equipment power by the battery pack, and a battery charger for recharging the battery pack.
A battery pack containing a plurality of batteries, such as Ni-Cd (nickel-cadmium) batteries, is currently well known. The battery pack is attached to a variety of electrical equipment to supply electrical power. In addition, a discharged battery pack is connected with a battery charger, re-charged, and used again.
It is a requirement that the battery pack conform to parameters, such as current and voltage, for activating the particular electrical equipment in use. For this reason, many varieties of battery packs have been developed. Various battery packs are manufactured with differing battery voltages and capacities which are designed to meet specifications of various electrical equipment. Depending on the internal batteries, etc. of battery packs having different voltages or capacities, different optimum charging currents and charging times are necessary. For this reason many different types of battery chargers have been developed. Use of a battery pack which does not meet electrical equipment or battery charger specifications invites the danger of electrical equipment malfunction, or a battery charging malfunction such as over-charging or insufficient charging of the battery pack. Further, this can be expected to contributed to electrical equipment or battery charger failure, or to battery pack lifetime reduction due to repeated out-of-specification charge-discharge cycles. Consequently, a strategy to only allow use of battery packs which meet electrical equipment and battery charger specifications is necessary.
Technology to solve this type of problem is described In Japanese Utility Model Laid-open No. 63-118162 (1988). In this disclosure, recessed and protruding regions are provided on the battery pack surface which mates with the main body of the electrical equipment. The battery pack's recessed and protruding regions assume different shapes depending on the type of internal batteries, etc, The main body of the electrical equipment is configured to connect with a battery pack having specific recessed and protruding regions. With this type of battery pack, attachment to the main body of the electrical equipment can be restricted by the shape of the recessed and protruding regions corresponding to the type of batteries accepted. The result of this is that battery packs which meet electrical equipment specifications can be selectively attached, and problems such as electrical equipment malfunction can be prevented,
However, with this type of battery pack having recessed and protruding regions to mate with the shape of the electrical equipment, recessed and protruding regions of various different shapes must be formed on different battery packs in order to distinguish compatible and incompatible batteries. This results not only in the drawback that forming the battery pack case is complicated, but also that it is not suitable for mass production since different cases are required corresponding to different battery packs.